Spark-plug.



J. R. AYOTTE.

SPARK PLUG.

APPLICATION F|LEn'MAR.4.191s.

Batented Feb. 25,1919.

sellar-enne.

I Specification of Letters Patent.

Application tiled March d, 1918. `Serial He. 220,155.

To all whom may conceive.'

Be itknown that-1, Jessen" REN iiror'rn,

a subject or' the King of Great Britain, 'residing; at Chioago. in the countyv of Cook and Sta-te oflllinois, have invented certain new and useful improvements in Spark-Plugs,

vot Which the following; is aspecification.

My invention relates to spark plugs for internal combustion engines.

@ne of the objects of my invention is to generally improve spark plugs, whereby to raise the standard of excellence, in eiiiciency, l

' appearance and certainty or' operation.

' gasket to 'cated Within the larger petticoat` Another object is to so construct the plug that the parts thereoit readily be sepa.i arated for cleansing or replacement and as readily assembled.

@then further and more specific AObjects will readily appear to persons skilled in the art, from a consideration of the following description when, taken in conjunction with the drawings, wherein- Figure 1 is an elevationo'f my improved plug. l M

Fig. 2 is a central vertical section thereof.

Fig. 3 is central Vertical section of the refractory insulating ocre.

, vFig'. /1- is a bottoni plan View.

Fig. 5 is a transverse section taken on line o oi Fig. 2.

nig. Sis a similar section taken on line 6 `oi: F193. 2.

F1a. l is a sectional vier: of a sprung;r

hold the servation cap.

ln all the views the same references are used to indicate similar parts.'

The screw threaded or fitting 10, for insertion in the cylinder of a rfas engine, may be made on an aiitoxnatic lathe of hexagon bar or in at' he cast. it is provided with an exterior-ly threaded ushing 11 and on its smaller threaded end 127 projectingfrom the salient end thereof. is an electric terminal 13, in the form of a loop providing an eye 14. This terminal will be again referred to when describing its functions.

A core 15 of relatively refractory insulatingsubstance, such as porcelain, lava, or the like, is provided on its outer end with a relatively small head 16 and near its inner cylinder in `the obend, with a relativelyv larger head 17. Near this end is a tent-like projection 18 to be lo- 19 afforded by the interior of the plug 10. llhe core is centrally bored, as at 20, for the axial conductor 21, the inner end 22 of which aiords Va' sparking terminal for c0- operation with a similar terminal 14.

vThe outer end of the bore 2O in the core 15 is enlarged and threaded, 'asat .23, to receive the enlarged threaded end 24:. 'of the central stem or conductor 21. The core is also provided With an axial projection 25, the use of Whichwill he disclosed farther on. A shoulder 26 is formed-around the an- 'nular head 16 by rthereduced portion 27 of the shank or body of the core. I :in assembling the core 15 in the plug; 1G al gasket 2S is first placed in the hollow p ug. teat 18 Within the opening 19 and spaced away therefrom to form a pettieoat. Another gasket 29 is threaded over the smaller end of the core until it isin contact-With ,Patented Feb. 25,191.96

rThe `core is then inserted with the' the shoulder 80. The bushing 11 may now y tact with the shoulder 30, and 'to force the shoulder 1?' in contact With the Washer or "gasket 28. `This holds the core irmly in the tting' 10. The central stern or conductor 21 niay be put in place, first having' its enlarged threaded end 24 coated 'with a suitable cement, leaving" the smaller part 21 therebelow, free to expand and contract its linear dimensions by temperature changes.

The extreme upper end of the-stein is rev duced and threaded, as at 31, to receive a threaded terminal -nut 32, a Washer 33 having,-v iirst heen placed over the reduced end 31 to prevent of the nut with the bare surface of 'the' eores end.

Means for securingI the hood '35 in place on the upper end of the core 15' is supplied by the spring ring 36 which consists of the exteriorly 'threaded ring portion 37 and the annular bead part '38. The salient inner edge 89 of the .head is smaller in diameter than the head 16 oli 'the core,'but is of the im) same diameter as the shank 27 behind the shoulder 26. Therefore the bead 38 is divided on a pluralit;i of' radial lines by a saw cut. as at 4-0, which out may extend part- Way through the ring 37, as at 4L the bead end of the ring is'forced over the head 16, the edges 39 Will-.snap behind the shoulder 2G, vso that When the nut e2, which is a part of the hood 35, is screwed on the ring 87, as shown in lifr. 2, the ring 36 can.- 13e not be remofed. p u

Before thehood 35 and nut 42 are placed When lid

yas

in position, a cushion gasket 43 is placed around the projection of the core and over this is placed a washer 4:4 to receive the glass cylinder e5 in the hood 35. 0n top of the glassy cylinder is placed a corrugated spring washer 46 to yieldingly bear upon the upper end of the cylinder to hold the latter in place and prevent rattling, and to ventilate the cylinder.

The upper eind of the hood is inturned and interiorly threaded, as at 47, to receive the adjustablethreaded 'stem 418, the lower end oi' which 49, provides a sparking electrode in coperation with the nut 32; Surrounding the stem a8 is an interiorly threaded `sleeve to receive the stem 48 and eXteriorly threaded for the hub 47. rihe sleeve bears a head 51 by which it and the stern may be rotated and whereby to lock it to the stem to hold the latter in adjusted position. A check nut 53 holds the sleeve to the hood adjusted position. A

clamping nut 5a surrounds the sleeve 50 and uintensity the effect oi the spark through the between the electrodes 13 and 22.

r}i)`he terminals 13 and 22 present rounding surfaces to each other, whereby a more intense and yabrupt discharge will ensue, there being no sharp edges to fringe and reduce the otential 'before the discharge occurs.

T e eye 14 may very easily and conveniently be -bent toward or from the stem 22, on the shank 13, to decrease or increase the extent of the gap.

The terminal 48 is pointed and the terminal 32 is blunt. This l have found contributes largely to the eiect of the spark between the terminals 14 and 22.

While l have hereinl shown a preferred embodiment of my invention, it is manifest that changes in the configuration and disposition may be made in some oi the parts within the scope and intendment of the appended claims. l

Having described 'my invention, what I claim is l. A spark plug having a central core provided on its upper end with an annular enmenaces larged head forming an abrupt shoulder; a threaded ring engaging said enlarged head having` an inturned beaded edge part to fit into said shoulder, said beaded edge part being split in a plurality of places to render 1t .diametrically expansible so that it may snap place, and a nut member threaded over the top end of said core and said ring covering the slots therein to rigidlyl hold the ring in place.

3. A spark plug having a central core proi vided with a head and Shoulder at one end;

an exteriorly threaded ring member iitting said head and having a beaded edge part provided With a plurality of splits and adaptedy to fit under and engage said shoulder, a hood member having. an interiorly threaded part to screw onto the ring member, a central conductor extending through the core and having its upper end within said hood and a rod threaded into said hood to coact with the upper end of said central conductor t0 form an auxiliary spark gap.

4:. A spark plug comprising a central core having an annularly enlarged head; an axially disposed conductor therein; an eX- teriorly threaded spring ring having a part to engage the core below the head to retain it on the core; a hood having a threaded part to engage the threaded ring; said hood having observation openings in its side wall; a transparent cylinder in said hood; a spring washer to resiliently engage said cylinder to prevent shocks from being imparted thereto, and spark gap terminals within said glass cylinder.

5. A spark plug having a centrally disposed core, a windowed hood mounted `on the top of the core; a glass cylinder within the hood, and a corrugated spring washer .overlying said cylinder and providing means for Ventilating the interior of the cylinder and for yieldingly holding it in place.

In testimony whereof. I hereunto set my hand.

JosEPH RENAYOTTE. 

